[gdal-dev] PDF-->JPEG-->KML. Confused about association between KML bounding box and PDF's neatline and corner coordinates.

Boris Dev boris.dev at gmail.com
Wed Oct 20 10:07:15 EDT 2010


My objective is to make a KML ground overlay with a geospatial PDF map.

Using GDAL's translate utility I have converted the PDF to a JPEG. The next
step and problem for me is to write the text of the KML ground overlay,
which requires a text of bounding box information like this:

<LatLonBox>
        <north>37.91904192681665</north>
        <south>37.46543388598137</south>
        <east>15.35832653742206</east>
        <west>14.60128369746704</west>

        <rotation>-0.1556640799496235</rotation>
      </LatLonBox>


As GDAL's output, I saw that the entire PDF with legend, title, etc and not
just the map image was converted.

As GDAL's output, I also saw 2 parts of data that seem they are useful to
match a bounding box to the map within the jpeg, but I cant figure out the
puzzle of how to make this work? Can I get the bounding box of the entire
PDF image with this information below?

Corner Coordinates:
Upper Left  (  666937.758, 2024687.983)
Lower Left  (  666991.811, 2018338.153)
Upper Right (  674511.276, 2024754.795)
Lower Right (  674565.328, 2018404.965)
Center      (  670751.543, 2021546.474)

<MDI key="NEATLINE">POLYGON ((672676.488065659650601
2019417.955749646294862,672636.091432046378031
2024030.267778463661671,667347.405745737953112
2023983.612156898481771,667385.539170471020043
2019370.524140953086317,672676.488065659650601
2019417.955749646294862,672676.488065659650601
2019417.955749646294862,672676.488065659650601
2019417.955749646294862,672676.488065659650601
2019417.955749646294862))</MDI>

I realize the coordinate above need to be converted to lat/long to be a KML
ground overlay onto Google Maps, which I think I can handle.

But I am unsure if I need to extract the map image from the jpeg using the
NEATLINE?
How are the Corner Coordinates translated into a bounding box?

Any suggestions?
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